Lecithin, as used in commerce, is the name given to a group of substances present in fats which are obtained mainly from oil seeds, for example, soybeans and rape seeds) and from egg yolks. Commercial lecithin is a natural emulsifying agent used in foodstuffs and pharmaceutical products, for example, in creams, balms, or ointments.
Lecithin has also been described in dispersions or suspensions in propellants. For example, broncho-dilators can be administered by inhalation means in a propellant containing lecithin.
It has now been found that lecithin enhances the penetration of a drug through the skin and across other biological membranes, such as intestinal, buccal, rectal, and nasal. Thus an object of the present invention is a method of administering a drug transdermally or transmucosally by using lecithin in the pharmaceutical composition.